The Japanese angelshark (Squatina japonica) is a species of angelshark, family Squatinidae, found in the northwestern Pacific Ocean off China, Japan, and Korea. It is a bottom-dwelling shark found in sandy habitats down to 300 m (980 ft) deep. This species has the flattened shape with wing-like pectoral and pelvic fins typical of its family, and grows to 1.5 m (4.9 ft) or more in length. Its two dorsal fins are placed behind the pelvic fins, and a row of large thorns occurs along its dorsal midline. Its upper surface is cryptically patterned, with numerous squarish dark spots on a brown background.

The dorsal fins of the Japanese angelshark are located behind the rear tips of the pelvic fins.

The Japanese angelshark is fairly narrow-bodied and has greatly enlarged pectoral and pelvic fins. The skin folds along the sides of the head lack distinct lobes. The eyes are oval and widely spaced; closely behind are crescent-shaped spiracles with large, boxy projections inside their anterior rims. Each nostril is large and preceded by a small flap of skin bearing two barbels; the outer barbel is thin, while the inner barbel has a spoon-like tip and a smooth to slightly fringed flange at the base. The wide mouth is terminally placed and has furrows at the corners. There are 10 tooth rows on either side of both jaws, separated by a gap in the middle; the teeth are small, narrow, and pointed. There are five pairs of gill slits located on the sides of the head.[3][6]

The frontmost portion of each pectoral fin forms a triangular lobe separate from the head. The outer corners of the pectoral fins are angular, and their rear tips are rounded. The pelvic fins have convex margins. The two angular dorsal fins are similar in shape and size, and are located behind the pelvic fins. The caudal peduncle is flattened with a keel running along either side, and supports a roughly triangular caudal fin with rounded corners. The lower lobe of the caudal fin is larger than the upper. The dorsal surface is covered by medium-sized dermal denticles, and a distinctive row of large thorns is present along the midline of the back and tail. This species is light to dark brown above with a dense covering of squarish dark spots, which become finer on the fins. The underside is white with darker mottling.[3][6] Various sources give differing maximum lengths, ranging from 1.5 to 2.5 m (4.9 to 8.2 ft).[1][7]

Angel sharks in general are highly threatened by commercial trawl fisheries due to their susceptibility to capture and low rate of reproduction, and angel shark species elsewhere are known to have declined markedly under fishing pressure. Trawling activity in the Yellow Sea and other parts of the northwestern Pacific is intense and, coupled with pollution, has had a serious impact on the local ecosystem. The Japanese angelshark population is suspected to have declined by up to 50% or more under these conditions, leading the species to be assessed as Vulnerable by the International Union for Conservation of Nature (IUCN). It may benefit from a ban on trawling imposed in some areas by the Chinese government, though enforcement is inconsistent.[1]

^ abcdeCompagno, L.J.V. (1984). Sharks of the World: An Annotated and Illustrated Catalogue of Shark Species Known to Date. Food and Agricultural Organization of the United Nations. pp. 147–148. ISBN978-92-5-101384-7.